TGF-β is a multifunctional cytokine, which is secreted by both TAMs and glioblastoma cells, and it promotes various processes in the tumor, like cancer cell proliferation, invasion, stemness, angiogenesis and immune suppression, but TGF-β also recruits TAMs to the TME and plays a role in M2-like polarization [45,54]. Here, TGFB1 is linked to glioblastoma.